Reconfigurable multi-channel all-optical regenerators

Abstract

An all-optical regenerating circuit including a wavelength converter based on a Mach-Zehnder interferometer. The input signal is amplified and the interferometer adjusted to place the input signal across an entire monotonic portion of a sinusoidal transfer function to the wavelength-converted output signal. Retiming is effected by wavelength converters including pulsed laser sources of the output wavelength. A multi-wavelength regenerator may be integrated on a chip including two arrayed waveguides and an array of tunable lasers on parallel waveguides therebetween.

1. An optical regenerator, comprising a wavelength converter receiving an optical input signal at a first carrier wavelength modulated by a data signal and including an optical source producing a probe signal at a second carrier wavelength, and at least one semiconductor active region and being capable of converting the carrier wavelength of said optical input signal from said first wavelength to said second wavelength on an optical output signal according to a wave-shaped transfer function between said optical input and output signals, wherein an amplitude of said optical input signal and a biasing of said at least one active region are selected to place said optical input signal to substantially extends across only one peak-to-peak portion of said respective transfer function. 
   
   
     2. The regenerator of  claim 1 , comprising:
 an optical demultiplexer receiving a multi-wavelength signal; 
 a plurality of said wavelength converters having respective inputs connected to different outputs of said demultiplexer; and 
 a multiplexer receiving outputs of the wavelength converters and combining said optical output signals into a multi-wavelength signal. 
 
   
   
     3. The regenerator of  claim 1 , wherein said wavelength converter includes a interferometer receiving both said optical input signal and said probe signal. 
   
   
     4. The regenerator of  claim 3 , wherein said interferometer is a Mach-Zehnder interferometer. 
   
   
     5. The regenerator of  claim 1 , wherein said optical source comprises a tunable laser. 
   
   
     6. The regenerator of  claim 1 , wherein said optical source comprises a mode-locked laser locked to said optical input signal. 
   
   
     7. A multi-wavelength optical regenerator, comprising:
 a demultiplexer receiving a multi-wavelength optical signal impressed upon respective and different first optical wavelengths and routing them according to wavelengths to a plurality of wavelength-separated optical input signals; 
 a plurality of wavelength converters each receiving a respective one of said optical signals, including a optical source having a second wavelength, and at least one semiconductor active region and being capable of converting the wavelength of said wavelength-separated optical input signal from said first wavelength to said second wavelength on a respective wavelength-separated output signal according to a respective wave-shaped transfer function between respective ones of said wavelength-separated optical input and output signals, wherein an amplitude of said respective wavelength-separated optical input signal and a biasing of said at least one active region is selected to place said respective wavelength-separated optical input signal substantially extends across only one peak-to-peak portion of said respective transfer function; and 
 a multiplexer receiving outputs of the wavelength converters and combining said optical output signals into a multi-wavelength signal. 
 
   
   
     8. The regenerator of  claim 7 , wherein said optical source is unmodulated and said wavelength converter includes an active semiconductor region for converting said wavelength of said wavelength-separated optical input signal. 
   
   
     9. The regenerator of  claim 7 , wherein said optical source comprises a tunable laser. 
   
   
     10. The regenerator of  claim 9 , wherein said demultiplexer additionally receives additional optical signals and said multiplexer outputs to a plurality of outj,uts, whereby said tunable lasers can selectively switch signals from any of said optical signals to any of said plurality of outputs. 
   
   
     11. The regenerator of  claim 9 , wherein said demultiplexer receives signals from a plurality of input ports and said multiplexer outputs to a plurality of output ports. 
   
   
     12. The regenerator of  claim 7 , wherein said regenerator acts as both a regenerator and an addldrop multiplexer. 
   
   
     13. The regenerator of  claim 7 , wherein said regenerator acts as an optical router including a wavelength router. 
   
   
     14. The regenerator of  claim 7 , wherein said wavelength-separated optical signals remain unswitched between said demultiplexer and said multiplexer. 
   
   
     15. The regenerator of  claim 7 , wherein said transfer function is sinusoidal. 
   
   
     16. The regenerator of  claim 7 , wherein said multiplexer and demultiplexer and at least portions of said wavelength converters are formed in a monolithic chip. 
   
   
     17. The regenerator of  claims 16 , wherein said multiplexer and demultiplexer comprise arrayed waveguide gratings. 
   
   
     18. The regenerator of  claim 7 , wherein said wavelength converters comprise Mach-Zehnder interferometers. 
   
   
     19. The regenerator of  claim 7 , wherein respective optical channels carrying respective ones of said wavelength-separated optical input and output signals are connected between said demultiplexer and multiplexer and are not switchable in between. 
   
   
     20. A regenerating wavelength converter, comprising:
 a mode locked laser; 
 a source laser outputting an unmodulated signal at a laser wavelength; 
 a first Mach-Zehnder interferometer receiving on a first input a data modulated optical signal and on a second input the output of the source laser and having an output received by the mode locked laser; and 
 a second Mach-Zehnder interferometer receiving outputs of said mode locked laser and said first Mach-Zehnder interferometer to produce an output signal that is data modulated similarly to said optical input signal at the laser wavelength determined by said source laser. 
 
   
   
     21. The converter of  claim 20 , further comprising a semiconductor optical amplifier receiving said data modulated optical input signal. 
   
   
     22. The converter of  claim 20 , wherein said data modulated optical input signal has a carrier wavelength of between 1535 and 1565 nm and said mode-locked laser produces pulses of radiation at a wavelength of less than 1535 nm. 
   
   
     23. An optical regeneration method, comprising the steps of:
 receiving an optical input signal having a data signal modulating a carrier at a first wavelength; 
 generating an optical probe signal at a second wavelength; and 
 interfering said optical input signal and said probe signal including passing them through a semiconductor active region to produce an optical output signal having said data signal modulating a carrier at said second wavelength, whereby said interfering produces a wave-shaped transfer function between amplitudes of said optical input signal and said optical output signal; and 
 biasing said semiconductor active region so that an amplitude of said optical input signal extends substantially across only one peak-to-peak portion of said transfer function. 
 
   
   
     24. The method of  claim 23 , further comprising:
 generating a clock signal locked to said optical input signal; and 
 gating said optical output signal according to said clock signal. 
 
   
   
     25. The converter of  claim 20 , wherein said source laser is a tunable laser.